| 摘要 |
<p>Additive replacing C dusts for forming bright C surface on metal casting moulds consists of a thermoplastic non-foamed unsubstd. hydrocarbon of particle size below 0.3 mm. Pref. plastic consists of styrene, ethylene or propylene (co)polymers, present in suspension or emulsion, esp. as products of pearl polymerisation. Pref. polymer is premixed with binder, partic. bentonite, and esp. polymerised pearls are surrounded by colloidal bentonite. Pref. plastic concns. in moulding comps. are 0.5-3 (0.5-2) %.</p> |
